Update.

1998-09-20 09:37  Ulrich Drepper  <drepper@cygnus.com>

	* elf/Versions [GLIBC_2.1] (libc): Add __fpu_control.
	* elf/elf.h: Add AT_FPUCW.
	* elf/Makefile (dl-routines): Add fpu_control.
	(elide-routines.os): Add fpu_control.
	(rtld-routines): Add fpu_control.
	* math/Makefile (aux): Remove fpu_control.
	* sysdeps/generic/dl-sysdep.c (_dl_sysdep_start): Handle AT_FPUCW.
	(_dl_show_auxv): Likewise.
	* sysdeps/unix/sysv/linux/init-first.c (init): Use __setfpucw only
	if different from OS default.

	* stdio-common/tstscanf.c: Add test case for (nil).

ChangeLog

@@ -1,3 +1,18 @@
+1998-09-20 09:37  Ulrich Drepper  <drepper@cygnus.com>
+
+	* elf/Versions [GLIBC_2.1] (libc): Add __fpu_control.
+	* elf/elf.h: Add AT_FPUCW.
+	* elf/Makefile (dl-routines): Add fpu_control.
+	(elide-routines.os): Add fpu_control.
+	(rtld-routines): Add fpu_control.
+	* math/Makefile (aux): Remove fpu_control.
+	* sysdeps/generic/dl-sysdep.c (_dl_sysdep_start): Handle AT_FPUCW.
+	(_dl_show_auxv): Likewise.
+	* sysdeps/unix/sysv/linux/init-first.c (init): Use __setfpucw only
+	if different from OS default.
+
+	* stdio-common/tstscanf.c: Add test case for (nil).
+
 1998-09-18 17:41  Ulrich Drepper  <drepper@cygnus.com>
 
 	* libio/fileops.c (_IO_new_file_underflow): Before allocating

elf/Makefile

@@ -28,13 +28,15 @@ routines	= $(dl-routines) dl-open dl-close dl-symbol dl-support \
 # profiled libraries.
 dl-routines	= $(addprefix dl-,load cache lookup object reloc deps \
 			          runtime error init fini debug misc \
-				  version profile)
+				  version profile) \
+		  fpu_control
 # But they are absent from the shared libc, because that code is in ld.so.
-elide-routines.os = $(dl-routines) dl-support enbl-secure
+elide-routines.os = $(dl-routines) dl-support enbl-secure fpu_control
 
 # ld.so uses those routines, plus some special stuff for being the program
 # interpreter and operating independent of libc.
-rtld-routines	:= rtld $(dl-routines) dl-sysdep dl-environ dl-minimal
+rtld-routines	:= rtld $(dl-routines) dl-sysdep dl-environ dl-minimal \
+		   fpu_control
 distribute	= $(rtld-routines:=.c) dynamic-link.h do-rel.h dl-machine.h \
 		  dl-hash.h soinit.c sofini.c ldd.bash.in eval.c \
 		  genrtldtbl.awk atomicity.h dl-procinfo.h ldsodefs.h \

elf/Versions

@@ -19,7 +19,7 @@ libc {
   GLIBC_2.1 {
     # global variables
     _dl_profile; _dl_profile_map; _dl_profile_output; _dl_start_profile;
-    _dl_loaded; _dl_main_searchlist;
+    _dl_loaded; _dl_main_searchlist; __fpu_control;
 
     # functions used in other libraries
     _dl_mcount; _dl_mcount_wrapper; _dl_mcount_wrapper_check; _dl_unload_cache;

elf/elf.h

@@ -777,6 +777,10 @@ typedef struct
 #define AT_HWCAP	16		/* Machine dependent hints about
 					   processor capabilities.  */
 
+/* This entry gives some information about the FPU initialization
+   performed by the kernel.  */
+#define AT_FPUCW	17		/* Used FPU control word.  */
+
 
 /* Note section contents.  Each entry in the note section begins with
    a header of a fixed form.  */

math/Makefile

@@ -29,7 +29,7 @@ headers		:= math.h bits/mathcalls.h bits/mathinline.h bits/huge_val.h \
 distribute	:= math_private.h machine/asm.h machine/endian.h
 
 # FPU support code.
-aux		:= fpu_control setfpucw
+aux		:= setfpucw
 
 # Build the -lm library.
 

stdio-common/tstscanf.c

@@ -219,5 +219,21 @@ main (int argc, char **argv)
       }
   }
 
+  fputs ("Test 6:\n", stdout);
+  {
+    char *p = (char *) -1;
+    int res;
+
+    sprintf (buf, "%p", NULL);
+    res = sscanf (buf, "%p", &p);
+    printf ("sscanf (\"%s\", \"%%p\", &p) = %d, p == %p\n", buf, res, p);
+
+    if (res != 1 || p != NULL)
+      {
+	fputs ("test failed!\n", stdout);
+	result = 1;
+      }
+  }
+
   exit (result);
 }

sysdeps/generic/dl-sysdep.c

@@ -28,6 +28,7 @@
 #include <sys/mman.h>
 #include <elf/ldsodefs.h>
 #include <stdio-common/_itoa.h>
+#include <fpu_control.h>
 
 #include <entry.h>
 #include <dl-machine.h>
@@ -126,6 +127,9 @@ _dl_sysdep_start (void **start_argptr,
       case AT_HWCAP:
 	_dl_hwcap = av->a_un.a_val;
 	break;
+      case AT_FPUCW:
+	__fpu_control = av->a_un.a_val;
+	break;
       }
 
   /* Linux doesn't provide us with any of these values on the stack
@@ -249,6 +253,12 @@ _dl_show_auxv (void)
 					  16, 0),
 			      "\n", NULL);
 	break;
+      case AT_FPUCW:
+	_dl_sysdep_message ("AT_FPUCW:     ",
+			    _itoa_word (av->a_un.a_val, buf + sizeof buf - 1,
+					10, 0),
+			    "\n", NULL);
+	break;
       }
 }
 

sysdeps/unix/sysv/linux/init-first.c

@@ -60,8 +60,10 @@ init (int argc, char **argv, char **envp)
 	 the executable format.  */
       __personality (PER_LINUX);
 
-      /* Set the FPU control word to the proper default value.  */
-      __setfpucw (__fpu_control);
+      /* Set the FPU control word to the proper default value if the
+	 kernel would use a different value.  */
+      if (__fpu_control != _FPU_DEFAULT)
+	__setfpucw (__fpu_control);
     }
 
   /* Save the command-line arguments.  */